A three-dimensional graphene oxide/carbon nanotubes-COOH hybrid (GO/CNTs-COOH) consisted of two-dimensional graphene oxide (GO) and one-dimensional carbon nanotubes-COOH (CNTs-COOH) was synthesized. The GO/CNTs-COOH hybrid exhibited excellent water-solubility owing to the high hydrophilicity of GO components and the carboxylation of carbon nanotubes. The cobalt hexacyanoferrate decorated GO/CNTs-COOH (CoHCF/GO/CNTs-COOH) has been prepared using electrostatic adsorption of Co2+ on GO/CNTs-COOH and K-4[Fe(CN)(6)] as an in-situ chemical precipitant. FT-IR, Raman spectroscopy, TEM, SEM, and cyclic voltammetry were utilized to characterize the nanohybrid. The electrochemistry behavior of hydrazine on different modified electrodes was also studied. The CoHCF/GO/CNTs-COOH modified GCE (CoHCF/GO/CNTs-COOH/GCE) exhibited greatly enhanced electrocatalytic performance towards electro-oxidation of hydrazine. The oxidation peak currents showed good linear relationships with concentration of hydrazine. It can be applied to detect hydrazine in samples sensitively. (C) 2015 Elsevier Ltd. All rights reserved.